The mid-anchoring method is usually confined to installations which contain a single tank. Layers of nonconductive material are placed over the top of the tank, after it has been set in the excavation. Reinforced concrete is then "wrapped" around the top 1/3 of the tank diameter giving extra weight to the tank. The nonconductive material isolates the concrete from the tank shell.
Generally, the mid-anchoring method is not as effective as other anchoring methods and is not recommended.